I don't think it's quite the same thing. Laptops in particular often have machined (?) surfaces that feel very weird to the touch, regardless of electricity. HP in particular is a regular offender, though I haven't touched many apple computers.
I've experienced it and it's markedly different how a laptop feels when plugged into the wall Vs not: it's because of a relatively high voltage (but also high impedance, so not dangerous, though sometimes painful if it focuses through a small point like a USB cable) hum you tend to see in the ground of most modern power adaptors due to noise reduction capacitors.
No, this is a different thing. It's leakage current from ungrounded power supplies (the two-prong apple power brick) and it's extremely noticeable. Couple hundred microamps, feels like licking a 9 volt battery.